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Black smoke coming out from exhaust pipe. When you buy a brand-new diesel truck, you might notice smoke coming out of the exhaust. This is normal. The rings take 500 to 1,000 miles to seat in the cylinders. Until they do, fuel, oil, and air force their way past the rings and into the crankcase – and then out the exhaust. As soon as the rings seat, this problem disappears. The smoke you need to be concerned about happens after the rings seat, as there should be no visible smoke from the exhaust at that time.

Mevert Automotive & Tire Center in Steeleville IL has certified technicians for Cummins diesel repair. The techs will determine why your vehicle’s diesel engine is blowing black, blue or white smoke.

Black Smoke

If you see black smoke coming out of the exhaust, it is full of carbon exhaust particles. You might see black smoke if the air-to-fuel ratio is incorrect and has more fuel. Older diesels were known to belch black smoke. However, we now have diesel exhaust fluid, diesel particulate filters and catalytic converters to prevent that. Thus, if you see black smoke, something is wrong.

Common causes of black smoke include:

  • Damaged or clogged fuel injectors.
  • Clogged air cleaners.
  • Clogged fuel or oil filters.
  • Damaged intercooler, turbocharger, injection pump, or EGR cooler.
  • Clogged EGR cooler.
  • Clogged or cracked valves.
  • Valve clearance is incorrect.
  • Over fueling (flooding) the engine.
  • Using the wrong blend of diesel for the temperature.

White Smoke

If you see white smoke coming from your diesel truck’s exhaust, one of the best Cummins diesel repair shops in Steeleville IL – Mevert Automotive & Tire Center. White smoke could mean one of two things: Fuel injectors or a head gasket problem.

The more common issue is fuel injector problems. If the diesel fuel is not being burned correctly, it will show in the exhaust as white smoke. It can irritate your eyes and skin. If you see white smoke while trying to start a diesel in freezing temperatures, you might have one or more bad glow plugs or your vehicle might have frozen soot deposits around the rings. If the vehicle stops smoking once it warms up, then that is most likely the issue, and the vehicle is fine to drive.

The other issue when you see white smoke could be from a bad head gasket. If the head gasket breaks on the exhaust side, water gets into the cylinders. Since water doesn’t burn, it leaves the engine in the form of white steam. A cracked head or cylinder block could also cause this issue, however, those issues are rare unless you overheated your engine.

Common causes of white smoke caused by injectors include:

  • Incorrect fuel pump or injector timing.
  • Damaged fuel pump timing.
  • Damaged injectors.
  • Damaged crankshaft keyway.
  • Low compression in the cylinders, which includes damaged, worn or washed-out rings.
  • Damaged timing gear.
  • Damaged cylinder liners.
  • Low fuel pressure to the fuel pump.
  • Damaged fuel lines.

Blue Smoke

If you see blue smoke coming out of the exhaust, the engine is burning oil. It is common to see it when starting a diesel engine in cold weather since the rings aren’t warm enough to conform to the sides of the cylinders. Once they heat up, this issue disappears.

However, when the blue smoke doesn’t disappear after the vehicle warms up, you have a big problem. If the engine has a lot of miles on it, worn rings might not seat properly anymore. Oil drips past the rings into the combustion chamber and is pushed out of the exhaust. It shows up as blue smoke.

In some cases, the cylinders might have glaze on them. Glaze is formed by the cylinders going up and down and naturally builds up in the cylinders over time. It will keep the rings from seating properly and cause the engine to burn oil – you’ll see the blue smoke.

Common causes of blue smoke include:

  • Damaged or worn piston rings, guides, or cylinders.
  • Damaged or worn valve seals.
  • Damaged lift pump.
  • The fuel has oil mixed into it.
  • The engine is overfilled with oil.
  • Using the wrong grade of oil.
  • Cylinder glazing.

Contact Mevert Automotive & Tire Center

If you see any color smoke that doesn’t disappear as soon as the vehicle warms up, contact Mevert Automotive & Tire Center in Steeleville IL for a Cummins diesel repair appointment. Our techs will determine what issue is causing the exhaust to smoke.